Hi Robb, please share the error log for the error.

Argument 2 passed to MFP\BlockUsers\is_blocked() must be an instance of ElggUser, instance of ElggSite given, called in /home/feedbaec/public_html/social/mod/block_users/start.php on line 183

Log at time 1550107827 may have more data.

TypeError Object
(
[message:protected] => Argument 2 passed to MFP\BlockUsers\is_blocked() must be an instance of ElggUser, instance of ElggSite given, called in /home/feedbaec/public_html/social/mod/block_users/start.php on line 183
[string:Error:private] => TypeError: Argument 2 passed to MFP\BlockUsers\is_blocked() must be an instance of ElggUser, instance of ElggSite given, called in /home/feedbaec/public_html/social/mod/block_users/start.php on line 183 and defined in /home/feedbaec/public_html/social/mod/block_users/lib/functions.php:49
Stack trace:
#0 /home/feedbaec/public_html/social/mod/block_users/start.php(183): MFP\BlockUsers\is_blocked(Object(ElggUser), Object(ElggSite))
#1 [internal function]: MFP\BlockUsers\check_page_owner('pagesetup', 'system', NULL)
#2 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/EventsService.php(113): call_user_func_array('MFP\\BlockUsers\\...', Array)
#3 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php(1979): Elgg\EventsService->trigger('pagesetup', 'system')
#4 [internal function]: _elgg_manage_pagesetup('view_vars', 'page/elements/t...', Array, Array)
#5 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php(52): call_user_func_array('_elgg_manage_pa...', Array)
#6 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/ViewsService.php(292): Elgg\PluginHooksService->trigger('view_vars', 'page/elements/t...', Array, Array)
#7 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php(337): Elgg\ViewsService->renderView('page/elements/t...', Array, false, 'default')
#8 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php(1163): elgg_view('page/elements/t...', Array)
#9 /home/feedbaec/public_html/social/mod/block_users/pages/block_users/blocked_user_content.php(10): elgg_view_title('You are trying ...')
#10 /home/feedbaec/public_html/social/mod/block_users/start.php(75): include('/home/feedbaec/...')
#11 [internal function]: MFP\BlockUsers\page_handler(Array, 'block_users')
#12 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Router.php(100): call_user_func('MFP\\BlockUsers\\...', Array, 'block_users')
#13 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Application.php(436): Elgg\Router->route(Object(Elgg\Http\Request))
#14 /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Application.php(384): Elgg\Application->run()
#15 /home/feedbaec/public_html/social/index.php(8): Elgg\Application::index()
#16 {main}
[code:protected] => 0
[file:protected] => /home/feedbaec/public_html/social/mod/block_users/lib/functions.php
[line:protected] => 49
[trace:Error:private] => Array
(
[0] => Array
(
[file] => /home/feedbaec/public_html/social/mod/block_users/start.php
[line] => 183
[function] => MFP\BlockUsers\is_blocked
[args] => Array
(
[0] => ElggUser Object
(
[url_override:protected] => 
[temp_metadata:protected] => Array
(
)

[temp_annotations:protected] => Array
(
)

[temp_private_settings:protected] => Array
(
)

[volatile:protected] => Array
(
)

[orig_attributes:protected] => Array
(
)

[attributes:protected] => Array
(
[guid] => 36
[type] => user
[subtype] => 0
[owner_guid] => 0
[site_guid] => 1
[container_guid] => 0
[access_id] => 2
[time_created] => 1549525866
[time_updated] => 1549525866
[last_action] => 1550107826
[enabled] => yes
[name] => Administrator
[username] => admin
[password] => 
[salt] => 
[password_hash] => $2y$10$mv76RphhDphbGozqYji9e.n5QUDkIeaoHhmyl0dUFc7KYqTRLC4a6
[email] => admin@feedbae.com
[language] => en
[banned] => no
[admin] => yes
[prev_last_action] => 1550107823
[last_login] => 1550099091
[prev_last_login] => 1550065334
)

[valid:protected] => 
[time:ElggData:private] => 
)

[1] => ElggSite Object
(
[url_override:protected] => 
[temp_metadata:protected] => Array
(
)

[temp_annotations:protected] => Array
(
)

[temp_private_settings:protected] => Array
(
)

[volatile:protected] => Array
(
)

[orig_attributes:protected] => Array
(
)

[attributes:protected] => Array
(
[guid] => 1
[type] => site
[subtype] => 0
[owner_guid] => 0
[site_guid] => 1
[container_guid] => 0
[access_id] => 2
[time_created] => 1549525866
[time_updated] => 1549887716
[last_action] => 1549979269
[enabled] => yes
[name] => FeedBae.com
[description] => Social site for size acceptance
[url] => http://feedbae.com/social/
)

[valid:protected] => 
[time:ElggData:private] => 
)

)

)

[1] => Array
(
[function] => MFP\BlockUsers\check_page_owner
[args] => Array
(
[0] => pagesetup
[1] => system
[2] => 
)

)

[2] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/EventsService.php
[line] => 113
[function] => call_user_func_array
[args] => Array
(
[0] => MFP\BlockUsers\check_page_owner
[1] => Array
(
[0] => pagesetup
[1] => system
[2] => 
)

)

)

[3] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php
[line] => 1979
[function] => trigger
[class] => Elgg\EventsService
[type] => ->
[args] => Array
(
[0] => pagesetup
[1] => system
)

)

[4] => Array
(
[function] => _elgg_manage_pagesetup
[args] => Array
(
[0] => view_vars
[1] => page/elements/title
[2] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[3] => Array
(
[view] => page/elements/title
[vars] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[viewtype] => default
)

)

)

[5] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/PluginHooksService.php
[line] => 52
[function] => call_user_func_array
[args] => Array
(
[0] => _elgg_manage_pagesetup
[1] => Array
(
[0] => view_vars
[1] => page/elements/title
[2] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[3] => Array
(
[view] => page/elements/title
[vars] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[viewtype] => default
)

)

)

)

[6] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/ViewsService.php
[line] => 292
[function] => trigger
[class] => Elgg\PluginHooksService
[type] => ->
[args] => Array
(
[0] => view_vars
[1] => page/elements/title
[2] => Array
(
[view] => page/elements/title
[vars] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[viewtype] => default
)

[3] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

)

)

[7] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php
[line] => 337
[function] => renderView
[class] => Elgg\ViewsService
[type] => ->
[args] => Array
(
[0] => page/elements/title
[1] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

[2] => 
[3] => default
)

)

[8] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/lib/views.php
[line] => 1163
[function] => elgg_view
[args] => Array
(
[0] => page/elements/title
[1] => Array
(
[title] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

)

)

[9] => Array
(
[file] => /home/feedbaec/public_html/social/mod/block_users/pages/block_users/blocked_user_content.php
[line] => 10
[function] => elgg_view_title
[args] => Array
(
[0] => You are trying to view content from or perform an action on a user that you have blocked. To see this user's content, you must first unblock the user.
)

)

[10] => Array
(
[file] => /home/feedbaec/public_html/social/mod/block_users/start.php
[line] => 75
[args] => Array
(
[0] => /home/feedbaec/public_html/social/mod/block_users/pages/block_users/blocked_user_content.php
)

[function] => include
)

[11] => Array
(
[function] => MFP\BlockUsers\page_handler
[args] => Array
(
[0] => Array
(
[0] => blocked_user_content
)

[1] => block_users
)

)

[12] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Router.php
[line] => 100
[function] => call_user_func
[args] => Array
(
[0] => MFP\BlockUsers\page_handler
[1] => Array
(
[0] => blocked_user_content
)

[2] => block_users
)

)

[13] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Application.php
[line] => 436
[function] => route
[class] => Elgg\Router
[type] => ->
[args] => Array
(
[0] => Elgg\Http\Request Object
(
[attributes] => Symfony\Component\HttpFoundation\ParameterBag Object
(
[parameters:protected] => Array
(
)

)

[request] => Symfony\Component\HttpFoundation\ParameterBag Object
(
[parameters:protected] => Array
(
)

)

[query] => Symfony\Component\HttpFoundation\ParameterBag Object
(
[parameters:protected] => Array
(
[__elgg_uri] => /block_users/blocked_user_content
[blocked_username] => rube2112
[next] => http://feedbae.com/social/profile/rube2112
)

)

[server] => Symfony\Component\HttpFoundation\ServerBag Object
(
[parameters:protected] => Array
(
[CONTEXT_DOCUMENT_ROOT] => /home/feedbaec/public_html
[CONTEXT_PREFIX] => 
[DOCUMENT_ROOT] => /home/feedbaec/public_html
[GATEWAY_INTERFACE] => CGI/1.1
[GEOIP_ADDR] => 166.137.102.95
[GEOIP_AREA_CODE] => 463
[GEOIP_CITY] => Cleveland
[GEOIP_CONTINENT_CODE] => NA
[GEOIP_COUNTRY_CODE] => US
[GEOIP_COUNTRY_NAME] => United States
[GEOIP_DMA_CODE] => 510
[GEOIP_LATITUDE] => 41.499500
[GEOIP_LONGITUDE] => -81.695396
[GEOIP_METRO_CODE] => 510
[GEOIP_POSTAL_CODE] => 44192
[GEOIP_REGION] => OH
[GEOIP_REGION_NAME] => Ohio
[HTTP_ACCEPT] => text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
[HTTP_ACCEPT_ENCODING] => gzip, deflate
[HTTP_ACCEPT_LANGUAGE] => en-US,en;q=0.9
[HTTP_CONNECTION] => keep-alive
[HTTP_COOKIE] => phpbb3_cbl4g_k=; phpbb3_cbl4g_u=2; phpbb3_cbl4g_sid=15f886f14c18428d674554bebebb1b03; cookieconsent_status=dismiss; cp_sessionid=6285087859215119; PHPSESSID=4763cd36aa5bf7230c20a085c10b8546; feedbae.com_k=; feedbae.com_u=2; feedbae.com_sid=709572581f38701c24ea05ce1e56530f; ossn_chat_bell=off; plupload_ui_view=thumbs; Elgg=9df686b28ac28a4572a98cbbb5406fe2; __zlcmid=qqi0vRRkvhtz9t
[HTTP_HOST] => feedbae.com
[HTTP_REFERER] => http://feedbae.com/social/activity
[HTTP_UPGRADE_INSECURE_REQUESTS] => 1
[HTTP_USER_AGENT] => Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.82 Safari/537.36 Vivaldi/2.3.1440.41
[HTTP_VIA] => HTTP/1.1 akrnz04msp3ts11.wnsnet.attws.com
[PATH] => /bin:/usr/bin
[QUERY_STRING] => __elgg_uri=block_users/blocked_user_content&blocked_username=rube2112&next=http%3A%2F%2Ffeedbae.com%2Fsocial%2Fprofile%2Frube2112
[REDIRECT_GEOIP_ADDR] => 166.137.102.95
[REDIRECT_GEOIP_AREA_CODE] => 463
[REDIRECT_GEOIP_CITY] => Cleveland
[REDIRECT_GEOIP_CONTINENT_CODE] => NA
[REDIRECT_GEOIP_COUNTRY_CODE] => US
[REDIRECT_GEOIP_COUNTRY_NAME] => United States
[REDIRECT_GEOIP_DMA_CODE] => 510
[REDIRECT_GEOIP_LATITUDE] => 41.499500
[REDIRECT_GEOIP_LONGITUDE] => -81.695396
[REDIRECT_GEOIP_METRO_CODE] => 510
[REDIRECT_GEOIP_POSTAL_CODE] => 44192
[REDIRECT_GEOIP_REGION] => OH
[REDIRECT_GEOIP_REGION_NAME] => Ohio
[REDIRECT_QUERY_STRING] => __elgg_uri=block_users/blocked_user_content&blocked_username=rube2112&next=http%3A%2F%2Ffeedbae.com%2Fsocial%2Fprofile%2Frube2112
[REDIRECT_SCRIPT_URI] => http://feedbae.com/social/block_users/blocked_user_content
[REDIRECT_SCRIPT_URL] => /social/block_users/blocked_user_content
[REDIRECT_STATUS] => 200
[REDIRECT_UNIQUE_ID] => XGTEszOOuJXkUrVDCNLkVgAAAQk
[REDIRECT_URL] => /social/block_users/blocked_user_content
[REMOTE_ADDR] => 166.137.102.95
[REMOTE_PORT] => 39655
[REQUEST_METHOD] => GET
[REQUEST_SCHEME] => http
[REQUEST_URI] => /social/block_users/blocked_user_content?blocked_username=rube2112&next=http%3A%2F%2Ffeedbae.com%2Fsocial%2Fprofile%2Frube2112
[SCRIPT_FILENAME] => /home/feedbaec/public_html/social/index.php
[SCRIPT_NAME] => /social/index.php
[SCRIPT_URI] => http://feedbae.com/social/block_users/blocked_user_content
[SCRIPT_URL] => /social/block_users/blocked_user_content
[SERVER_ADDR] => 184.154.13.150
[SERVER_ADMIN] => webmaster@feedbae.com
[SERVER_NAME] => feedbae.com
[SERVER_PORT] => 80
[SERVER_PROTOCOL] => HTTP/1.1
[SERVER_SIGNATURE] => 
[SERVER_SOFTWARE] => Apache
[UNIQUE_ID] => XGTEszOOuJXkUrVDCNLkVgAAAQk
[PHP_SELF] => /social/index.php
[REQUEST_TIME_FLOAT] => 1550107827.221
[REQUEST_TIME] => 1550107827
)

)

[files] => Symfony\Component\HttpFoundation\FileBag Object
(
[parameters:protected] => Array
(
)

)

[cookies] => Symfony\Component\HttpFoundation\ParameterBag Object
(
[parameters:protected] => Array
(
[phpbb3_cbl4g_k] => 
[phpbb3_cbl4g_u] => 2
[phpbb3_cbl4g_sid] => 15f886f14c18428d674554bebebb1b03
[cookieconsent_status] => dismiss
[cp_sessionid] => 6285087859215119
[PHPSESSID] => 4763cd36aa5bf7230c20a085c10b8546
[feedbae_com_k] => 
[feedbae_com_u] => 2
[feedbae_com_sid] => 709572581f38701c24ea05ce1e56530f
[ossn_chat_bell] => off
[plupload_ui_view] => thumbs
[Elgg] => 9df686b28ac28a4572a98cbbb5406fe2
[__zlcmid] => qqi0vRRkvhtz9t
)

)

[headers] => Symfony\Component\HttpFoundation\HeaderBag Object
(
[headers:protected] => Array
(
[accept] => Array
(
[0] => text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
)

[accept-encoding] => Array
(
[0] => gzip, deflate
)

[accept-language] => Array
(
[0] => en-US,en;q=0.9
)

[connection] => Array
(
[0] => keep-alive
)

[cookie] => Array
(
[0] => phpbb3_cbl4g_k=; phpbb3_cbl4g_u=2; phpbb3_cbl4g_sid=15f886f14c18428d674554bebebb1b03; cookieconsent_status=dismiss; cp_sessionid=6285087859215119; PHPSESSID=4763cd36aa5bf7230c20a085c10b8546; feedbae.com_k=; feedbae.com_u=2; feedbae.com_sid=709572581f38701c24ea05ce1e56530f; ossn_chat_bell=off; plupload_ui_view=thumbs; Elgg=9df686b28ac28a4572a98cbbb5406fe2; __zlcmid=qqi0vRRkvhtz9t
)

[host] => Array
(
[0] => feedbae.com
)

[referer] => Array
(
[0] => http://feedbae.com/social/activity
)

[upgrade-insecure-requests] => Array
(
[0] => 1
)

[user-agent] => Array
(
[0] => Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.82 Safari/537.36 Vivaldi/2.3.1440.41
)

[via] => Array
(
[0] => HTTP/1.1 akrnz04msp3ts11.wnsnet.attws.com
)

)

[cacheControl:protected] => Array
(
)

)

[content:protected] => 
[languages:protected] => 
[charsets:protected] => 
[encodings:protected] => 
[acceptableContentTypes:protected] => 
[pathInfo:protected] => 
[requestUri:protected] => /social/block_users/blocked_user_content?blocked_username=rube2112&next=http%3A%2F%2Ffeedbae.com%2Fsocial%2Fprofile%2Frube2112
[baseUrl:protected] => 
[basePath:protected] => 
[method:protected] => 
[format:protected] => 
[session:protected] => 
[locale:protected] => 
[defaultLocale:protected] => en
[isForwardedValid:Symfony\Component\HttpFoundation\Request:private] => 1
)

)

)

[14] => Array
(
[file] => /home/feedbaec/public_html/social/vendor/elgg/elgg/engine/classes/Elgg/Application.php
[line] => 384
[function] => run
[class] => Elgg\Application
[type] => ->
[args] => Array
(
)

)

[15] => Array
(
[file] => /home/feedbaec/public_html/social/index.php
[line] => 8
[function] => index
[class] => Elgg\Application
[type] => ::
[args] => Array
(
)

)

)

[previous:Error:private] => 
)

Can you share the link from where you have downloaded the 2.x compatible block user plugin. All the plugins that I found was for elgg 1.x

If you are using the 1.x compatible plugin with elgg 2.x then for the above case, you can add these line in your start.php file at line 175

if ($page_owner instanceof \ElggSite) {
 return null;
}

The problem sounded familiar. Check my comments at https://elgg.org/plugins/2380396/releases/1.0.0 as these seemed to have worked to fix the issue(s) in the past.

The version I have is from the github page, it was mentioned in the thread about elgg 3.0 rc2 being released......someone needs to do a little better job  doicumenting this stuff.  If there's a fix, then why isn't ithe plugin updated???  I have no idea if the github version is the 1x version or not.  Why don't I know?  Because it comes with zero documentation.